An injection device has an injection cylinder for driving a plunger, a gas pressure type accumulator which supplies hydraulic fluid to the injection cylinder, a hydraulic fluid supply device which supplies the hydraulic fluid to the accumulator, a pressure sensor for detecting the gas pressure of the accumulator, and a control device which controls the hydraulic fluid supply device so as to suspend the supply of the hydraulic fluid when detection value of the pressure sensor reaches a predetermined target gas pressure before injection in the state where the hydraulic fluid is supplied from the hydraulic fluid supply device to the accumulator in a molding cycle.

A hydraulic drive apparatus includes a first hydraulic pump, a drive motor connected to the first hydraulic pump, a hydraulic line system connecting the first hydraulic pump to the consumer, and a closed-loop control unit. The closed-loop control unit has a first switching element to change a displacement volume of the first hydraulic pump between a predetermined minimum value and a maximum value. A second hydraulic pump is connected to the drive motor, and the hydraulic line system connects the second hydraulic pump to a consumer and has a first branch line connected to the first hydraulic pump, a second branch line connected to a second hydraulic pump, and a main line. The two branch lines open into the main line, and the closed-loop control unit has a second switching element for changing a displacement volume of the second hydraulic pump between a predetermined minimum value and a maximum value.

In a plastic injection machine, a controller in electrical communication with a motorized clamp assembly, a heated cylinder barrel, a motorized pre-plasticizing assembly, an injection assembly, and an air mover and that executes an application that configures the controller to: (i) feed thermoplastic material into a heated cylinder barrel that is closed at one end by an injection valve; (ii) warm the heated cylinder barrel to thermoplastic material to a liquid state; (iii) actuate an injection motor to preload a spring biased plunger received within another end of the heated cylinder barrel, thereby pressurizing liquid thermoplastic material in the heating cylinder barrel to an injection pressure set value; (iv) actuate an injection valve motor to open the injection valve causing the pressurized liquid thermoplastic material to inject into a clamped mold; and (v) release a portion of the clamped mold to release the molded article.

A run-around circuit makes a hydraulic fluid discharged from a rod-side chamber along with a forward movement of a piston in an injection cylinder flow into a head-side chamber. A servo valve is provided in the run-around circuit and is connected to a tank. In a first state, the servo valve permits flow from the rod-side chamber to the head-side chamber, while prohibits flow from the rod-side chamber to the tank. In a second state, the servo valve prohibits flow from the rod-side chamber to the head-side chamber, while permits flow from the rod-side chamber to the tank. The servo valve can control the flow rate of the hydraulic fluid discharged from the rod-side chamber in each of the first state and second state.

An injection apparatus (100) for injecting molten plastic, in particular PET, into a mold for molding bottle preforms; the injection apparatus (100) comprisinga first injector (1) and a second injector (2) adapted to receive molten plastic and inject it into the mold alternately to each other; a conduit (8) adapted to carry molten plastic from a plasticization apparatus (102) towards the first injector (1) and towards the second injector (2); a third injector (3) provided with a piston (32), the third injector (3) being connected to the conduit (8) so as to receive molten plastic from the conduit (8) and then inject it into the conduit (8); actuation means (34) adapted to cause the piston (32) of the third injector (3) to move forward to inject the molten plastic into the conduit (8); wherein said actuation means (34) are adapted to control the backward movement of the piston (32) of the third injector (3) while it receives the molten plastic from the conduit (8).

A driving force transmission unit includes a rotary plate provided with a rotation axis at an eccentric position, and a support portion having a hole portion through which the rotation axis passes and being configured to support a plunger. The hole portion extends in a moving direction of the plunger. The support portion swings in an extending direction of the hole portion by rotation of the rotary plate. When dispensing processing is terminated, an angle is larger than 90 degrees and smaller than 180 degrees, the angle being formed between a linear line connecting the rotation axis and a center of the rotary plate to each other and the moving direction of the plunger as viewed in a direction of the rotation axis. A control unit controls a rotation speed of a motor according to the angle during the dispensing processing.

A drive device includes an output for an injection piston of an injection device to be acted upon to generate an injection force, a hydraulic drive mechanically connected to the output for the injection piston, and an electric drive. The electric drive is mechanically connected to the output for the injection piston via the hydraulic drive, so that the drive force generated by the electric drive can be transmitted together with the drive force generated by the hydraulic drive via the hydraulic drive to the output for actuating the injection piston. The electric drive is at least partially integrated into the hydraulic drive, and has an electric motor and a coupling device. The coupling device of the electric drive is arranged completely in a cylinder of the hydraulic drive.

Provided are a dual injection system and a synchronization control method thereof. The system includes a primary injection system and a secondary injection system, where the primary injection system and the secondary injection system each include a speed injection oil circuit and a booster oil circuit; the speed injection oil circuit of the primary injection system and the speed injection oil circuit of the secondary injection system are arranged independently of each other; and the booster oil circuit of the primary injection system and the booster oil circuit of the secondary injection system each include an A-bridge valve group and are arranged in coordination with each other. The method is configured to perform a synchronization control on the primary injection system and the secondary injection system of the system.

A pressure holding device includes a stopper member that restricts a movement backward amount of a pressure holding plunger. When a pressure holding path is filled with a resin material, a second engagement member of the stopper member restricts the movement backward amount of the pressure holding plunger at a first position where the second engagement member is engaged with a first engagement member fixed to the pressure holding plunger. When a pressure of the mold is released after pressure holding, the second engagement member moves from the first position to a second position retracted from the first position to release a restriction on the movement backward amount of the pressure holding plunger.

Provided are a dual injection system and a synchronization control method thereof. The system includes a primary injection system and a secondary injection system, where the primary injection system and the secondary injection system each include a speed injection oil circuit and a booster oil circuit; the speed injection oil circuit of the primary injection system and the speed injection oil circuit of the secondary injection system are arranged independently of each other; and the booster oil circuit of the primary injection system and the booster oil circuit of the secondary injection system each include an A-bridge valve group and are arranged in coordination with each other. The method is configured to perform a synchronization control on the primary injection system and the secondary injection system of the system.